In general, a semiconductor device employs a supply voltage of 3.3V or less. However, the semiconductor device may include a high voltage transistor employing a high supply voltage of 5V or more.
The high voltage transistor is formed with a low voltage transistor. A lever shifter is provided between a circuit part driven by a high voltage and a circuit part driven by a low voltage to serve as a voltage buffer in a circuit employing a high voltage together with a low voltage.
However, if the level shifter is used, the size of a power chip is increased, thereby causing delay to internal signals.